Thanks for a clear an well written draft. I have reviewed this from the perspective of my knowledge of PCEP and the way PCCs and PCEs generally work, rather than going through the YANG with a fine-toothed comb, as I am not really a YANG expert and I would hope that a YANG doctor's review would cover the syntax and other correctness of the YANG. I have just a few nits/questions, below, but otherwise I think the draft is ready for publication.

The line numbers are from the IDNits output.

[snip]
16	Abstract
18	   This document defines a YANG data model for the management of Path

s / Path / the Path

19	   Computation Element communications Protocol (PCEP) for communications

[snip]

91	1.  Introduction

93	   The Path Computation Element (PCE) defined in [RFC4655] is an entity
94	   that is capable of computing a network path or route based on a
95	   network graph, and applying computational constraints.  A Path
96	   Computation Client (PCC) may make requests to a PCE for paths to be
97	   computed.

99	   PCEP is the communication protocol between a PCC and PCE and is
100	   defined in [RFC5440].  PCEP interactions include path computation
101	   requests and path computation replies as well as notifications of
102	   specific states related to the use of a PCE in the context of
103	   Multiprotocol Label Switching (MPLS) and Generalized MPLS (GMPLS)
104	   Traffic Engineering (TE).  [RFC8231] specifies extensions to PCEP to
105	   enable stateful control of MPLS TE LSPs.

107	   This document defines a YANG [RFC7950] data model for the management
108	   of PCEP speakers.  It is important to establish a common data model
109	   for how PCEP speakers are identified, configured, and monitored.  The
110	   data model includes configuration data and state data.

112	   This document contains a specification of the PCEP YANG module,
113	   "ietf-pcep" which provides the PCEP [RFC5440] data model.  Further,
114	   this document also includes the PCEP statistics YANG module "ietf-
115	   pcep-stats" which provides statistics, counters and telemetry data.

117	   The PCEP operational state is included in the same tree as the PCEP
118	   configuration consistent with Network Management Datastore
119	   Architecture (NMDA) [RFC8342].  The origin of the data is indicated
120	   as per the origin metadata annotation.

MB> I take the above text to mean that this draft is a YANG model for PCEP when the
data plane is assumed to be MPLS. However, it doesn't quite say that. It seems
to imply that MPLS is the only valid data plane, when in fact SRv6 could be used and there are drafts
related to that. I would suggest rephrasing or adding text to say the PCEP in general 
could be used with other data planes, but we are only modelling MPLS here, or something along those lines. Just to make it very clear what the scope of the model is.

[snip]
553	         |  +--rw inter-layer?            boolean {inter-layer}?
554	         |  +--rw h-pce {h-pce}?
555	         |     +--rw enabled?    boolean
556	         |     +--rw stateful?   boolean {stateful}?
557	         |     +--rw role?       hpce-role
558	         +--rw msd?                          uint8 {sr}?

MB> The model implies that a PCC could have a MSD configured that is different from
the MSD that is advertised in the IGP, for example. I thought MSD was really a router/LER-wide 
property, determined by the underlying datapath implementation, rather than something to configure, so should this not be YANG state for the PCC (i.e. ro rather than rw )? This question is also applicable to line 771 in the draft.